Matrix summation within a loop

Question

0 个投票

Hello Friends, I want to solve "Phi=Summation((1/ai^2)*V(:,i)*U(:,i)') for loop range i=1:100". At every iteration Phi is a 100x500 huge matrix.

How such huge matrix summation problem can be solve?

Any and all replies are really appreciated!

~Keshav

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Answer 1

Andrei Bobrov 2012-2-18

1 个投票

Phi2 = zeros(size(V,2),size(U,1));
for j1 = 1:size(V,2)
    Phi2(j1,:) = 1/ai^2*sum(V(:,j1)*U(:,j1).');
end

OR

without loop

Phi1 = 1/ai^2*sum(bsxfun(@times,permute(V,[2 3 1]),U.'),3)

Answer 2

0 个投票

It's working. Thanks a lot Bobrov!

One think i m nt getting, whts is meaning of dot in "U." ?

Regards, KDSingh